In an optical communication network, there is a type of signal light that is formed from different optical signal packets in time. Time of each optical signal packet is inconsecutive and a particular time interval without a light exists. Power amplitude between two adjacent optical signal packets may be inconsecutive. It is called a burst optical signal. At present, the burst optical signal exists in an optical switching system that is formed from an optical packet switching (OPS) technology or an optical burst switching (OBS) technology and a passive optical network (PON) system of an access network. A device, an instrument, or a system that generates this type of burst optical signal is uniformly called an optical burst signal source. Conventionally, the optical burst signal source includes an optical burst transmitter, an optical burst switch, and so on.
Signal optical power of the burst optical signal is gradually attenuated with an increase of a transmission distance in an optical fiber. To extend the transmission distance of the optical signal, amplification needs to be performed on the optical signal; or, when the burst optical signal passes through an optical component, the signal optical power is attenuated due to an insertion loss of the optical component, and in this case, amplification also needs to be performed on the optical signal. A preferred solution is to use an optical amplifier (a burst optical amplifier) that supports the burst optical signal. An existing optical amplifier is implemented by using a solution of automatic power control (APC) that is also called constant power control. In this solution, output optical power of the optical amplifier is a fixed value, which is specifically as follows: An optical detector is used to monitor intensity of an amplified signal light; when the intensity of the signal light is smaller than the fixed value, a pump source is controlled to increase power of a generated pump light; when the intensity of the signal light is greater than the fixed value, the pump source is controlled to adjust the power of the generated pump light; the pump light and the signal light are input into a wavelength division multiplexer (WDM); the WDM combines the input signal light and pump light and then inputs the combined light into a gain medium; the gain medium absorbs energy provided by the pump light to enable electrons to jump to a high energy level and generate population inversion; a signal photon triggers these activated electrons through a stimulated radiation process and enable the electrons to jump to a lower energy level; in this way, an amplified signal is generated and the amplification of the signal light is implemented.
During the implementation of the present invention, the inventor discovers that: Because the output optical power needs to be kept in a constant state, when no signal light is input, the optical amplifier may drive the pump source to output a pump light with large power so that optical power of amplified spontaneous emission (ASE) generated by the gain medium is equal to the output optical power of the fixed value. In this case, the power of the pump light is higher than that when a signal light is input. In a process from the situation where no signal light is input to the situation where a signal light is input, a serious gain overshoot surge lasting tens of microseconds is caused because the power of the pump light at this time is higher than that when a signal light is input, which causes severe damage on a transmission signal and distortion of the optical signal.